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Abstract The present paper deals with the assessment of original and a modified version RELAP5/MOD3.3 against OSU Multi Application Small Light Water Reactor (OSU-MASLWR). new implemented features regard suitable correlations for heat transfer coefficient evaluation in helical geometry. Furthermore, two different modelling Helical Coil Steam Generator (HCSG) are assessed. In first approach, HCS...

Despite system thermal–hydraulic codes were extensively validated for transient simulations of LWR, several activities highlighted limited capabilities these tools to model heat transfer within in-pool passive power removal system. Discrepancies with experimental results related the underestimate pool boiling and film condensation coefficients. Thus, DIAEE “Sapienza” University Rome developed a...

The work completed had the following objectives: i) To compute pulse width (full width at half maximum-FWHM) of the power curves for the Three Mile Island Unit 1 Pressurized Water Reactor (TMI-1 PWR) core model in the event of a super-prompt-critical rod ejection accident (REA) at Hot Zero Power (HZP) in the central fuel assembly (Rod 7A) at both EOC and BOC for various control rod worths and d...

Thermal hydraulics of nuclear reactor as a basis of reactor safety has a very important role in reactor design and control. The thermal-hydraulic analysis provides input data to the reactor-physics analysis, whereas the latter gives information about the distribution of heat sources, which is needed to perform the thermal-hydraulic analysis. In this study single heated channel model as a very f...